[PATCH 1/6] bio: optimize initialization of a bio

[Jens Axboe <axboe@kernel.dk>]

The memset() used is measurably slower in targeted benchmarks. Get rid
of it and fill in the bio manually, in a separate helper.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/bio.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index 1fab762e079b..0b1025899131 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -238,6 +238,35 @@ static void bio_free(struct bio *bio)
 	}
 }
 
+static inline void __bio_init(struct bio *bio)
+{
+	bio->bi_next = NULL;
+	bio->bi_bdev = NULL;
+	bio->bi_opf = 0;
+	bio->bi_flags = bio->bi_ioprio = bio->bi_write_hint = 0;
+	bio->bi_status = 0;
+	bio->bi_iter.bi_sector = 0;
+	bio->bi_iter.bi_size = 0;
+	bio->bi_iter.bi_idx = 0;
+	bio->bi_iter.bi_bvec_done = 0;
+	bio->bi_end_io = NULL;
+	bio->bi_private = NULL;
+#ifdef CONFIG_BLK_CGROUP
+	bio->bi_blkg = NULL;
+	bio->bi_issue.value = 0;
+#ifdef CONFIG_BLK_CGROUP_IOCOST
+	bio->bi_iocost_cost = 0;
+#endif
+#endif
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	bio->bi_crypt_context = NULL;
+#endif
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+	bio->bi_integrity = NULL;
+#endif
+	bio->bi_vcnt = 0;
+}
+
 /*
  * Users of this function have their own bio allocation. Subsequently,
  * they must remember to pair any call to bio_init() with bio_uninit()
@@ -246,7 +275,7 @@ static void bio_free(struct bio *bio)
 void bio_init(struct bio *bio, struct bio_vec *table,
 	      unsigned short max_vecs)
 {
-	memset(bio, 0, sizeof(*bio));
+	__bio_init(bio);
 	atomic_set(&bio->__bi_remaining, 1);
 	atomic_set(&bio->__bi_cnt, 1);
 
-- 
2.32.0